make invisible depending on point of view
Assuming that the room's normals point inwards, you can accomplish this by using the Geometry node, a Mix Shader and a Transparent BSDF.

Connect the Backfacing socket of the Geometry node to the Fac socket of the Mix Shader node. Next connect your actual material nodes to the upper Shader input of the Mix Shader node and the Transparent BSDF to the lower one. 

This effectively creates a backface culling material.

If you're using Eevee, you will also have to set the Blend Mode and Shadow Mode to Alpha Clip or Alpha Hashed. In case you're only using Eevee and don't need a material for Cycles, you can enable the Backface Culling option (above the Blend Mode) instead of using the node setup.

Don't forget to add lights inside the room.







If you only want this for the viewport, then you can enable Backface Culling in the Viewport Shading options.